Commit-ID: 924726b2b5e5000dfb8eb6032651baed1b1bdc6c
Gitweb: http://git.kernel.org/tip/924726b2b5e5000dfb8eb6032651baed1b1bdc6c
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Sun, 23 Apr 2017 12:13:09 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Sun, 23 Apr 2017 13:24:34 +0200
perf: Cure hotplug lock ordering issues
The get_online_cpus() rework unearthed lock ordering issues.
Reorder hotpluglock and perf_sched_mutex() to avoid circular locking
dependencies and convert static_branch_disable() to the cpuslocked version
to avoid hotplug lock recursion.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
kernel/events/core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 8aa3063..b5b4f52f 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4016,10 +4016,12 @@ static void unaccount_event(struct perf_event *event)
static void perf_sched_delayed(struct work_struct *work)
{
+ get_online_cpus();
mutex_lock(&perf_sched_mutex);
if (atomic_dec_and_test(&perf_sched_count))
- static_branch_disable(&perf_sched_events);
+ static_branch_disable_cpuslocked(&perf_sched_events);
mutex_unlock(&perf_sched_mutex);
+ put_online_cpus();
}
/*
--
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